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EP-3779252-B1 - MULTIPORT VALVE FOR WATER QUALITY ANALYZER

EP3779252B1EP 3779252 B1EP3779252 B1EP 3779252B1EP-3779252-B1

Inventors

  • MAEDA KAZUMA

Dates

Publication Date
20260506
Application Date
20190304

Claims (1)

  1. A multiport valve (1) used for a water quality analyzer, comprising: a valve head (4) having a plurality of ports (6) for receiving pipings for connections therebetween, the ports (6) being provided on an outer surface of the valve head (4), the valve head (4) including a connection surface (4a) in which ends of flow paths (8) communicating with the respective ports (6) are arranged in the same plane, the valve head (4) being made of PCTFE having corrosion resistance against a chemical used in the water quality analyzer; a rotor (14) having a flat surface provided with a groove (16) for switching a connection state between the ends of the flow paths (8) arranged on the connection surface (4a), the flat surface being arranged so as to face the connection surface (4a); a drive mechanism (18, 22) configured to rotate the rotor (14); characterized in that the multiport valve (1) further comprises a stator (10) fixed to the valve head (4), the stator (10) being interposed between the flat surface of the rotor (14) formed with the groove (16) and the connection surface (4a) of the valve head (4), wherein the material of the rotor (14) is softer than the material of the stator (10), the material of the stator (10) is ceramic, and the material of the rotor (14) is PEEK, PPS, PTFE, or PCTFE.

Description

Technical Field The present invention relates to a multiport valve used for a water quality analyzer. Background of the Invention In a water quality analyzer, processing, such as, e.g., collection of a sample, suction of a reagent, addition of a reagent to a sample, delivery of a sample to an oxidation reaction section, and delivery of the sample to a measurement section, is performed using a syringe pump. The processing is performed by switching the flow paths communicating with the syringe pump by a multiport valve (see Patent Document 1). A highly corrosive reagent, such as, e.g., strong acid and strong alkali, is frequently used in a water quality analyzer. Therefore, all of the components configuring the water quality analyzer that come into contact with a reagent must be configured by a material having corrosion resistance against a reagent. For this reason, in a multiport value for a water quality analyzer is configured such that the metallic portions do not come into contact with a reagent. Specifically, a multiport valve is composed of a valve body, a valve head, a rotor, a stator, etc. The valve head is a metallic member attached to the tip of the valve body. The valve head is provided with a plurality of female threaded holes for securing piping. The stator is assembled to the valve head and has flow paths therein to communicate with piping connected to the female threaded holes of the valve head. The rotor includes a groove for communicating between flow paths formed in the stator to switch the flow paths of the stator by rotating while sliding with the stator. Further prior art documents are US 2016/082439 A1, US 2009/071341 A1, US 5 441 071 A and CN 106 382 391 A. Prior Art Document Patent Document Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013-015387 SUMMARY OF THE INVENTION Problems to be Solved by the Invention In a multiple port valve used for a water quality analyzer, to prevent highly corrosive chemicals from coming into contact with a metallic valve head, the piping is fixed to the female threads in a state in which the tip end of the piping is pressed against the stator with a strong force to seal the connecting part between the flow path and the stator. With the structure, the tip ends of the plurality of piping are pressed against the stator from a plurality of directions. In particular, when the stresses are uneven, the stator may be deformed or the ferrule attached to the tip of the piping may be deformed, resulting in a liquid leakage in the multiple port value. When a liquid leakage occurs in the multiport valve, the metallic valve head may corrode or rust, causing problems such as poor water sampling, crystallization of the reagent, and sticking of joint components. This may cause the stator to stick to the valve head. In the worst case, it becomes impossible to replace the stator. Therefore, it is the object of the present invention to prevent a liquid leakage in a multiport valve due to stresses being applied from a plurality of directions to a stator. This object is achieved by the subject-matter of claim 1. A multiport valve used for a water quality analyzer according to the present invention is defined in claim 1. Effects of the Invention In the multiport valve for a water quality analyzer according to the present invention, the valve head is configured by a material having corrosion resistance and piping is connected to the flow paths provided in the valve head. Therefore, the stator is not configured to be pressed by the tip ends of piping from several directions, and consequently, no liquid leakage occurs due to such a configuration. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional configuration diagram showing an example of a multiport valve for a water quality analyzer.FIG. 2 is a cross-sectional diagram showing another example, not being claimed and being a comparative example, of a multiport valve for a water quality analyzer.FIG. 3 is an image showing a state of flow paths when a valve head made of PPS has been used for a long time.FIG. 4 shows a state of flow paths when a valve head made of PCTFE has been used for a long time. EMBODIMENTS FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a multiport valve for a water quality analyzer will be described with reference to the attached drawings. A multiport valve 1 for a water quality analyzer according to one example is provided with a valve body 2 and a valve head 4. The valve head 4 is attached to the tip end of the valve body 2. A plurality of ports 6 is provided on the outer surface of the valve head 4. Each port 6 is a female screw hole for connecting piping to the outer surface of the valve head 4. The plurality of ports 6 is in communication with the respective flow paths 8 formed in the valve head 4, and the ends of the flow paths 8 are arranged on the flat surface 4a of the valve head 4 forming the rearmost surface of the inner space of the valve body 2.